4-nitro-4-pentenal



United States Patent-O 3,187,053 4-NITRO-4-PENTENAL Karl Klager, Sacramento, Calif., assignor to Aerojetgfiiieral Corporation, Azusa, Califi, a corporation of o No Drawing. Filed Dec. 21, 1959, Ser. No. 861,138 1 Claim. (Cl. 260-601) This application is a continuation-in-part of my copend ing application Serial No. 387,023, filed October 19, 1953 and now abandoned, which was a continuation-in-part of application Serial No. 235,569, filed July 6, 1951, and now abandoned.

This invention relates to a novel method of preparing nitroolefins having the general formula NO: CHFJ3R wherein R is an alkyl, halogen, w-carboxyalkyl, w-acyloxyalkyl, w-carboalkoxyalkyl, cyanoalkyl, or o-formy-lalkyl radical, and to nitroolefins prepared thereby.

The nitroolefins prepared by the method of this invention in which R is an w-acyloxyalkyl radical, such as nitroallyl acetate, readily condense with nitro compounds having a labile hydrogen function, such as methyl 4,4- dinitrobutyrate, to form highly nitrated compounds, such as dimethyl 4,4,6,8,8-pentanitro-1,1l-undecanedioate, useful as high explosives. A more complete description of this process can be found in my copending application Serial No. 636,839, filed January 28, 1957 and now Patent No. 3,000,932. In addition, all of the nitroolefins prepared by the method of this invention undergo an addition reaction with polynitro compounds having a labile hydrogen function, such as 2,2,4,4-tetranitrobutyl acetate, to form highly nitrated compounds useful as high explosives. 2,2,4,4-tetranitrobutyl acetate is disclosed in assignees copending application Serial No. 617,667, filed October 22, 1956 and now Patent No. 2,978,455. The addition reaction is conducted according to the method set forth in copending application Serial No. 636,839.

The highly nitrated compounds obtained by the abovedescribed methods are useful as high explosives and can be used in any conventional explosive missile, projectile, rocket, or the like, as the main explosive charge. An example of such a missile is disclosed in United States Patent 2,470,162, issued May 17, 1949. One way of using the high explosives of this invention in a device such as that disclosed in United States Patent 2,470,162 is to pack the crystalline explosive in powder form into the warhead of the missile. Alternatively, the crystals can be first pelletized and then packed. A charge thus prepared is sufficiently insensitive to withstand the shock entailed on the ejection of a shell from a gun barrel or from a rocket launching tube under the pressure developed from ignition of a propellant charge, and can be caused to explode on operation of an impactor time-fuse mechanism firing a detonating explosive such as lead azide or mercury fulminate.

The novel method of this invention comprises the simple pyrolysis of nitro-substituted endo anthracene compounds to decompose them into anthracene and the corresponding nitroolefins, in accordance with the general reaction scheme set forth below:

wherein R is as defined above.

The pyrolysis is preferably conducted under a vacuum so as to avoid the possibility of undesirable oxidation. The heat, as may be seen above, breaks the nitroolefin- Patented June 1, 1965 ICC anthracene bonds to yield anthracene and the desired nitroolefins.

The following examples are provided to more clearly illustrate my invention. It should be understood, however, that these examples are provided purely for purposes of illustration and are not intended to limit the scope of the invention in any way.

EXAMPLE I Preparation of methyl-4-nitro-4-penten0ate One part of 11-(2-carbomethoxyethyl)-11-nitro-9,10- ethanoanthracene was heated in vacuum at 21 mm. to l-200 C. A slightly yellow colored liquid was distilled and condensed in a receiver. The weight was 0.28 part of the starting material. At 230-240 C., at the same pressure, 0.62 gm. solid material distilled which was identified as anthracene (M.P. 215 C., mixed melting point 215 C.). The first fraction was redistilled at 96 C. and 4 mm. The analysis indicated that methyl-4- nitro-4-pentenoate was formed, n =1.46l2.

EXAMPLE II Preparation of nitroallyl acetate A bulb tube charged with 1 gm. ll-acetoxy-methyl-llnitro-9,10-ethanoanthracene, prepared by acetylation of II-methylol-l1-nitro-9,IO-ethanoanthracene with acetic anhydride, M.P. 103105 C., was heated to ZOO-220 C. at 29 mm. in an airbath. Decomposition was observed and a greenish-yellow liquid distilled, accompanied by crystals. After redistillation at -120 C. airbath temperature and 5 mm. the light-yellow liquid (0.1 gm.) gave the following analysis for nitroallyl acetate:

Analysis.Calcd =for C5H104N: percent C, 41.38; percent H, 4.86; percent N, 9.65. Found: percent C, 41.53; percent H, 5.45; percent N, 8.83. The anthracene fraction was purified by crystallization from tetrahydrofuran and methanol. The melting point and mixed melting point with pure anthracene were 214- 216 C.

EXAMPLE III Preparation of 4-nitro-4-pentenonitrile A bulb tube was filled with 0.8 gm. .11-(2-cyanoethyl)- 11-nitro-9,lO-ethanoanthracene and heated to 195-200 C. at 28 mm. A yellow liquid and crystals distilled. The distillate was dissolved in ether and filtered from the insoluble anthracene. The extract was evaporated and distilled at C. airbath temperature and 5 mm. producing a greenish-yellow liquid with a refractive index, 1.4735.

Analysis.-Calcd for C H O N percent C, 47.61; percent H, 4.80; percent N, 22.22. Found: percent C, 47.97; percent H, 4.94; percent N, 22.62.

The ether insoluble portion was crude anthracene. It was dissolved in tetrahydrofuran and methanol was added. After two recrystallizations the melting point was 213- 214 C. and the mixed melting point with anthracene (M.P. 2l4216 C.) was 214216 C.

It will be apparent that any nitroolefin within the scope of the general formula given above can be prepared by heating the corresponding nitro-substituted 9,10-ethanoanthracene in the manner described in the above examples. For example, 2-nitro-1-butene; 2-nitro-1-hexene; 2-nitropropylene; l-chloro-l-nitroethylene; l-bromo-l-nitroethylene; l-fluoro-l-nitroethylene; ethyl-4-nitro-4-pentenoate; methyl-2-methyl-3-nitro-3-butenoate; 4-nitro-pentenoic acid; and 4-nitro-4-pentenal can be prepared by heating 1 1-ethyl-l1-nitro-9, 10-ethanoanthracene; ll-butyl- 11-nitro-9,10 ethanoanthracene; 11-methyl-11-nitro-9,10- ethanoanthracene; 11-ch1oro-11-nitro-9,10 ethanoanthracene; 1 l-bromo-l l-nitro-9, 10-ethanoanthracene; 1 l-fluoro- 1 1-nitro-9, IO-ethanoanthracene; 1 1- (Z-carboethoxyethyl) 11-nitro-9,10 ethanoanthracene; 11-(2-carbomethoxyl-1- methylethyl)-11-nitro-9,l0 ethanoanthracene; 11-(2-carboxy-ethyl)-11-nitro-9,IO-ethanoanthracene; and 11-(2- formylethyl) -1 1-nitro-9, IO-ethanoanthracene, respectively, in accordance with the method of this invention.

Nitro-substituted endo anthracene compounds suitable as starting material for the method of this invention are readily obtained by condensing 11-nitro-9,10-ethanoanthracene with an alkyl halide such as ethyl iodide, a halogen such as chlorine, an alkenoic acid ester such as ethyl acrylate, an unsaturated nitrile such as acrylonitrile, an alkenoic acid such as acrylic acid, an alkanal such as formaldehyde, or an a, fl-unsaturated aldehyde such as acrylic aldehyde, as more fully disclosed in my copending application Serial No. 861 ,137 filed concurrently with the present application.

As will be apparent to those skilled in the art, some of the compositions prepared by the method of this invention are known. However, those compositions within the scope of the general formula given above in which R is an w-carboxyalkyl, w-carboalkoxyalkyl, cyanoalkyl, or w-formylalkyl radical are novel.

The halogen-substituted nitroolefins prepared by the method of this invention, such as l-chloro-l-nitroethylene, find valuable use as pharmaceutical intermediates and also as intermediates in the preparation of wetting, detergent, and emulsifying agents, as disclosed in U.S. Patent 2,510,281, issued June 6, 1950, and U.S. Patent 2,510,282 of the same date.

I claim:

As a composition of matter, 4-nitro-4pentenal.

References Cited by the Examiner Klager: J. Org. Chem., vol. 20, May 1955, pp. 650-56.

LEON ZITVER, Primary Examiner.

WILLIAM G. WILES, CHARLES B. PARKER,

Examiners. 

